Double suction liquid pump



Juixe 23, 1942. Y E. RUPP 2,287,397V

` DUBLE SUCTION LIQUID IJMP A Filed Marsh 29, 1940 5 Sheets -Sheet 1 HERBERT E RUPP flater/anys..

5 Sheets-Sheetl 2 June 23, 1942.

H. E. RUPP DOUBLE SUCTION LIQUID PUMP Filed March 29, 1940 June 23, 1942. n EQ Rupp DOUBLE sucTIoN LQUID uur 5 Sheets-Sheet y3 Filed March 29, 194G- r. UPP

HERBERT E H. E. RUPP June 23, 1942.

DOUBLE sUcTIQN LQUID PUMP Filed llarch 29, 1940 5 Sheets-Sheet 4 me/wm HERBERT E. RUPP Patented June 23, 1942 UNITED STTES ATET QFFICE DOUBLE SUCTION LIQUID PUMP Herbert E. Rupp, Springfield Township, Richland County, Ohio This invention relates to centrifugal liquid pumps or to improvements in such pumps of the double suction type which are also self-priming, and has reference as well to that class of related deviceswhich are formed with split casings. It forms a companion to the invention of my copending application, Serial No. 326,743, for a Liquid suction pump, filed simultaneously herewith.

An object of the invention is to provide an improved centrifugal self-priming pump of the stated type, in which the priming action of evacuating air and gas from its suction line or inlet is performed in Very quick time; that is, a pump adapted to prime for regular pumping operation in a manner exceptionally rapid and forceful and which in its pumping operation has a high degree of efciency in no way impaired by its self-priming ability. Incident to this stated object it is aimed to provide a pump capable of handling considerably more air and gas than any ordinary like pump of relative size and capacity, so that it will not only more quickly and effectually prime but will thereafter be less affected in the ordinary pumping function by any air or gas that may be drawn into its suction line not sufficient-to actually break the established suction.

Another object is to provide a centrifugal selfpriming pump in a horizontally-splitcasing construction, without the use of auxiliary jets or some mechanical attachment for the removal of air or gas, from the pumps interior.

Still another object is to provide a pump of the stated kind which will be capable of handling or expelling silt, pebble-rock and other solid material or debris that may be drawn thereinto through its suction line, which otherwise would be likely to 'accumulate and clog or stop the same.

A further object is to provide a pump wherein the working parts are few and easily accessible for repair or replacement and which in general is simple and inexpensive in construction.

Additional objects contributive to those stated will either be specially mentioned or made to appear clearly in the following speciiication, wherein the invention for full and better understanding will now be describedV in fuller detail with reference to the attached drawings, illustrating one practicable embodiment thereof, with certain modifications, in the form of a trench pump.

In said drawings:

Fig. 1 is a side elevation of the pump;I

Fig. 2 is a corresponding view in vertical section taken through the center;

Fig. 3 is a vertical section end View taken on the line 3-3 of Fig. 2;

Fig. 4 is a plan sectional View vtaken on the line 4-4 of Fig. 2;

Fig. 5 is a fragmentary View corresponding to Fig. 4 with the moving parts removed; v

Fig. 6 is a fragmentary view similarvto Fig. 2 showing the central part behind the rotor assembly or on the more rearward plane taken upon the line 6-6 of Fig. 3, the removable parts being removed;

Fig. 7 is a front end'elevation of one of the ring-member parts;

Fig. 8 is a fragmentary view corresponding to the lower center part of Fig. 3 illustrating a modification; f

Fig. 9 is a front side elevation of one of the parts of said modification;

Fig. 10 is a view similar to Fig. 8, illustrating another modification; and

Fig. 11 is a front end elevation of a part of Said another modification.

Inthe illustrative embodiment, the pump body is formed by a lower casing part I and an upper casing part 2, lfitted together upon a horizontal plane and united as by conventional flange-bolting (not shown) to each other with the usual gasket provision therebetween.- y

The lower of said casing .parts is formed with an intake passage 3 bifurcated around a center walling edge Ia into separate branches 3a and 3b opening thereinto centrally with ran upward curvature at opposite sides (see Figs. 2 and 4) and with an opposite discharge passage 4. opening therefrom at the center. the two said passages being disposed upon the same level and their external openings or ends being disposed upon the same plane with the fitting of the two casing parts on opposite sides of theY center line of the pump. Said lower casing part is also formed with two arms Io extended laterally from opposite sides, providing support for a shaft, later described, having its axis extending through said branch inlet openings and lying substantially within the fitting plane of the two casing parts. Rest portions or feet Ic on this lower casing part provide for mountive support of 'the unit on a suitable foundation.

The upper of said casing parts comprises a dome-shaped member the upper part of which provides a chamber 5 serving as an air and liquid separating space during the priming action of the pump and constituting a mere liquid body space in the pumping operation of the same. It is formed with opposite side wall cavities 6a and 6b in its lowerpart (see Fig. 3) registering top-wise with the openings of the branch inlets 3a and 3b into the center of the pump and continuatively completing the upward curvature thereof in the form of a constricting spiral around the axis or the shaft supported therewithin (see Fig. 6), so as to direct concentratively into the "eye of the impeller, the said cavities and the said inlet openings, paired 6ad with 3a and 6b with 3b, thus together forming and constituting the same single passages. Behind said opposite openings Ga and 6b in its lower part the said upper casing part is also formed with opposite side passages 'I, provided for by shoulder oflsets, leading from the upper chamber space down to stufling-box housings IZ-formed partly by the upper and partly by the lower casing parts-around the aforementioned shaft (see Figs. 3, 6 and 4) so as to provide a liquid seal against possible suction of air therearound into the pump.

Between the two casing parts an impeller housing or channelway 8 is held in clamped relation, with a spacing or separation all around from the casing walls, the same being positionally supported between a pair of underlying truss-ribs Id of the lower casing part (see Figs. 3, and 2) and a pair of overlying truss-ribs 2a of the upper casing part (see Figs. 3 and 2) engaging substantially therearound at opposite sides so as to balance and hold it rigidly in place. Also, against any possible rotational tendency, a lug projection I5a thereon is advantageously clamped or engaged between abutment portions I e and 2b of the respective casing parts. Said impeller housing or channelway comprises a circumferential trough-like member around or centered with the axis of the aforementioned shaft, constituting a plurality of discharge passages or channels such as 9 and I0 of volute form in this instance surrounding the periphery of the impeller. It is shown formed in this instance with only two of said channels, due to the complication of illustrating a greater number, but in other constructions and certain instances of desirability therefor it is proposed to form it with a greater number of these channels. For example, the two shown might be duplicated with opposite corresponding channels on either side, as in the case of a width divided channelway, or a third, fourth or fth channel might be added in circumferential relation, as when the channelway is of a larger diameter.

In the present embodiment composing only the two named channels, each extends substantially the full length of one side of the channelway member, or 18() degrees (see Fig. 2), one opening upwardly from the bottom along one side and the other opening downwardly from the top along the other side. These passages begin each with a cut-off point or edge II, close to which the tips of the impeller blades sweep in their rotated movement, and enlarge or expand outward progressively from their said points. The upwardly opening channel 9 terminates in a wide discharge mouth 9a opening directly into the upper chamber 5. The downwardly opening channel l0 terminates in a narrower discharge mouth Il)a opening into the pump casing bottom with directioning toward the main discharge passage 4. Between the constituting walls of the channelway member and the outside walls of the casing proper, the open spaces I3 and I4 at opposite sides provide channels through which liquid may dow (see Figs. 2 and 4).

The impeller mounted in said impeller channclway comprises a double suction rotor member I5, of a closed type in this instance, having a plurality of backwardly curved vanes I5a partially overlapping one another (see Fig. 2), the direction of rotation in the present assembly being indicated by the arrow. The closing side walls of this rotor are formed each with a central projecting hub-like collar I5u providing axial or eye openings thereinto from opposite sides through which liquid is admitted between its vanes. Surrounding or engaging around said collar projection at opposite sides are seal plates It tting in recesses formed in the two casing parts around the central inlet openings-3a with 6a and 3b with G11-into the pump and closing or isolating said openings from the remaining pump space so as to discharge directly into the impeller, the corresponding collar-like portions I6a of said plates immediately surrounding said collar projections of the impeller being desirably bored or recessed to t closely therearound without actual bind in order to minimize possible draw of liquid therebetween by suction. These plates are formed in this instance with lug projections IE5b (see Figs. 3 and 7) from their base margins bearing against the side edges of the channelway member so as to hold them pressed tight in place within their retaining recesses. It will be understood however that some other means of securing them in position may be substituted; for instance, they might be bolted in place.

" The said rotor, thus laterally encompassed, is

mounted upon its shaft in close lit within the channelway member, leaving a peripheral (circumferential) clearance I1 therearound (see Figs. 2 and 3) great enough merely to ensure free rotation and to permit a certain amount of liquid from the surrounding space to be drawn laterally therethrough by suction.

The described impeller is rotatably supported on a motive shaft I8 extending through the inlet openings and itself supported at opposite sides by the arms Ib of the lower casing part as previously indicated, the same being in effect clamped between the two casing parts. In extension through the walls of the casing, said shaft is encircled by seal packings I9 in the stuing-boxes I2 which are adapted to be kept constantly ooded with liquid from the passages 'I so as to provide also a liquid seal preventing the entrance of airfrom outside should any leakage develop from wear or loosening in the packings themselves. These packings are compressed by gland nuts 2) fitted over the shaft into said stuffing boxes and tightened through draw nuts on bolts 2| provided on the supporting arms Ib. The opposite ends of the shaft are journaled or supported in bearings 22 cradled in said arms and held in position by clamping cap-plates 23. Closure plates 24 are desirably provided for these bearing housings in order to protect them from dust and the like. In this connection it will be observed that conventional provision is made for tightening the shaft against its bearings, the same consisting of the thrust collar I 8a at one end and the screw-adjustable thrust nut 25 at the other. The said shaft is connected at one end with a motive unit or driving means (not shown) as indicated by the feather-slot 26. Ordinarily it will be preferred to connect it direct with a gas driving motor, but it may of course be pulley and belt driven from a detached power source. Y

Fitted over the outer end opening of the intake passage 3 is a valve chamber or suction elbow Z1, attached as by flange bolting (not shown) with the usual gasket provision between it and the lower casing part. `This valve chamber or elbow contains a check-valve 28 for closing the inlet passage against return or outward liquid ow, the same being of the simple flap type in this instance opening inwardly and seating against a valve-seatr29 which is conveniently provided in the present embodiment' by the inner end of a nipple 30 forming Ya part of said valve chamber or elbow. Connected to said nipple is the usual suction pipe or hose 3| extending from the liquid source to be pumped.

Similarly tted over the outer end opening of the opposite discharge passage 4 is a vertical discharge stack 32. This stack is of a height slightly greater than the upper casing part 2, such that when the latter is filled with liquid in its upper space 5, it will retain the same due to check of ou'tow by the lling also of the former to the same level. Between said stack and the top of the upper casing part a vent pipe connection 33 is provided for the escape of air through the stack that `might otherwise Vbecome trappedlby the liquid in the top ofthe casing space 5 with a compressive or downward force pressure effect. An opening closed by the plug 34 in this connection with said casing part provides for initially lling the pump therethrough with priming liquid. A similarplugged opening may if desired be formed in the bottom to provide a drain. To the upper end of thevertical stack a discharge pipe or hose (not shown) is connected, through which both air and liquid impelled by the impeller wheel is carried off from both said stack and the chamber 5 of the pump casing. l

The operation of this pump, in its priming and pumping cycles, is as follows:

Assuming that the `pump space has been filled with priming liquid, which will preferably be to near the top of chamber 5, the impeller is set into rotation by its driving means. In this connection it should be stated that the normal speed rate of drive may be anywherefrom 2000 to 3600 R. P. M., or as much as 5000 R P. M., giving the impeller a high peripheralvvelocity; but it will be understood that the speed rate may be varied according to requirements or working conditions` and to suit different capacities or characteristics and purposes of the pump, so that no limitation is made or intended in this regard beyond what is necessary to proper functioning Action of the impeller drives the liquid out of its sphere of rotation into the surrounding liquid channels or channelway member and upwardly therefrom into the space 5 above,lifting said liquid levelpossibly to a partial entry also into the ventY pipe Sii-and substantially sustaining it bodily so lifted in gravity suspension tending constantly to flow back into the excluded space. At the same time it sets up liquid currents, induced by swirling movement, substantially as indicated by the broken-shafted arrows in Fig. 2, one passing upwardly through the discharge mouth 9a, another passing upwardly from the discharge mouth Il)a through the channel space I3 and a third moving downward in the channel space I4.

Air in the impeller and mixed-by its centrifugal force-with the liquid surrounding it within said channelway member is carried in bubble form by said upward currents intonthe top of 75,

the chamber 5, where it is liberated and escapes ofiY through the discharge connection 33, aided by the opposing trends of said currents which tend to counteractach other and still the liquid in the upper part of said chamber.v A certain amount of the air-freed liquid of course Ilows downward from said chamber to the bottom of the casing through the channel space I4, where it unites with `the current flow upward from the bottom discharge mouth II)a in the natural tendency to ll a forced void. The discharge from the upper mouth 9a and the form of the impeller housing or channelway tend to prevent air from descent with such downward flow.

As the impeller continues to force air into the surrounding liquid, drawing it at both sides centrally from the bifurcated suction inlet and driving it out with the dischargive liquid currents set up by its rotation, a certain amount of air-free liquid is drawn in from the casing'space through the clearance I1 around its periphery as indicated by the shorter broken-shafted arrows in Fig. 2 to replenish the liquid forced out of the channels 9 and I0 at the orbit, this indrawn liquid being in turn whirled out in the current flow and mixing with or taking up air from between the impeller vane's so as to carry it off therewith. Actually this indrawn liquid serves for a compression and pushing or batting of the air by the vane tips into the discharging liquid Vwithin said peripheral channels 9 and I0. Possibly a certain amount of the liquid in spray form will be drawn also through the seall plate clearances around the collar projections I5'into the center of the impeller, in which event it would simply be thrown Ainto the surrounding. liquid, carrying some of the air with it, but such if any would be negligible and is not intended; rather is it sought to be avoided. A f

This priming action continues until all air from the casing, inlet passage and connected suction line has been exhausted or expelled out, the time therefor Abeing exceedingly short, whereupon the pump will begin pumping operation substantially like the ordinary Vdouble suction centrifugal pump and the liquid flow or movement will undergo a slight change.

In the pumping operation, the liquid is of course drawn into the center sides of the impeller through its suction line and bifurcated inlet passage from the pumping source. Thisliquid is discharged out by the centrifugal force of` the impeller through its surrounding peripheral channels 9 and I0 and through the vertical stack 32 with connected pipe or hose extending from the discharge passage 4, al small amount of discharge perhaps occurring also through the vent pipe connection 33. 'Ihe current trends of the liquid in thus expelling off are indicated by the full-shafted arrows in Figs. 2 and 3, being somewhat the same as in the priming cycle except that the two upward flows reduce to one only which turns back downward around both sides of the impeller channelway and merges with the discharge from the bottom`mouth Illab in a predominantly strong movement into and up the discharge passage, while the formerly downward ow through the channel space I4 becomes decidedly stronger and more definite. The liquid is forced or pumped out under the full force of the impeller which divides its discharge between the plurality of peripheral channels 'therearound, maintaining a continuous volume ejection as long as liquidis drawn into' its center.

Due'to the larger .opening of the top discharge mouth 9a than the bottom discharge mouth Ina, the force of discharge through the upwardly directed channel 9 is less than the force of discharge throughthe downwardly directed channel l0. This tends in a measure to permit the downward discharge to overbalance the upward discharge into chamber 5, which latter is shorter in the priming cycle but longer in the pumping cycle. Thus the downward discharge exerts a certain pull upon liquid descending along the channel space I4, which augmented by the increased force and volume of the upward discharges return flow down through said space in the priming cycle or `operation sets up a strong jetting action in the pump bottom sufficient to remove and expunge up the discharge stack any solid matter that may be drawn into the pump casing. This is an important feature of improvement which ensures that the pump will be lkept clear of the collection of debris that might clog and stop it.

The described pumping action gives a high lifting force and capacity to the pump which is particularly eiiicient in such operation as compared with other pumps of the same general type or class. Liquid that is mucky or laden with foreign matter is handleduwith the same effect as any clear liquid and there are no controlling valves or other movable parts to wear and impair the working eiiiciency. Once the pumping operation has started it continues until the pump is stopped or loses its prime and will be resumed again as soon as the drive is restored or the prime is reestablished. As to loss of prime during the pumping function, the ability to handle a large amount of air and gas and to prime very quickly renders the pump less affected by such air as may at times be drawn into its suction line not suflicient to` actually break the prime.

Referring now to the modification of Figs. 8 and 9t provision similar to the disclosure in my aforementioned companion application Serial No. 326,743 may if desired be incorporated to control the liquid adjacent the sides of the impeller, by a complete lateral enclosure of the same. Composing such a provision are shown in this instance a pair of plates 35 oppositely engaged over the collar-like portions 16a of the seal plates I6 engaging around the hub-like projecti'ons of the impeller and held in tight contact against the sides of the impeller channelway by the lug-projections 16h of said seal plates fitting into notches 35a therein having base-cut surfaces inclined correspondingly to the lower edge inclination of said lug-projections. Liners may if so desired be interposed between the contact surfaces, but a tight t will render this unnecessary. Each of said plates 35 has a-n'orifice 35 formed therein at its lower side. These plates thus positioned at opposite sides of the impeller effectually enclose it, forming spaces 31 therearound from which the liquid is excluded except as admitted through the bottom orifices 35. These latter can be made as large or small as desired to control the amount and rate of'liquid admission therethrough. Accordingly, the amount of liquid present in said spaces to be drawn through the peripheral clearance I1 between the impeller and its channelway member may be controlled, or restricted to any lower segment of the impeller. In all other respects the construction of the pump is the same.

Figs. 10 and 11 illustrate another modification having the same provisional purpose, wherein alternatively the seal plates I6 are formed with complete annular flanges |6 in place and instead of the lug-projections I 6b, said flanges contacting the side edges of the impeller channelway all the way around with pressure corresponding to that of said lug-projections and having orifices 38 therein at the lower sides corresponding to the orifices 36 of the previous modication. Thus similarly said seal plates alone are made to provide the spaces 31 at opposite sides of the impeller through which the liquid adjacent thereto is controlled.

In addition to a rapid self-priming ability and efficient pumping operation, due to its structural formation with a plurality of impeller discharge channels or passages, the described pump has the following particular advantages. sidewalls adjacent the impeller to resist the liquid action and reduce or impair its effective centrifugal force. There are no parts subject to excessive wear and those few which form the pump are easily accessible for repair or replacement, The pump can be 'easily and quickly dismantled. The capacity and performance characteristics of the pump may be changed readily by the insertion of an impeller channelway of different form with differently formed peripheral channels and cooperating rotor element. The construction lends itself to a very simple method of machining in that the suction and discharge are on the same plane with the center structure and line of the pump, permitting the entire surfacing to be machined in one setting and operation and making a cheaper unit to manufacture. The entire assembly is simple and inexpensive in construction.

Other modifications and various changes in the form and arrangement of the parts, with different combinations and sub-combinations of the same, can plainly be made without going beyond the actual scope of this invention. It will therefore be understood that the appended claims are not'intended to restrict the invention to the specific construction or arrangements shown, nor to otherwise impose limitations upon the same beyond what said claims themselves in specific terms define.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a double-suction centrifugal liquid pump, the improvement which consists in a horizontally split casing having intake and discharge passages formed at the same level and with outward end or fitting openings upon the same plane with the fitting of the two casing parts together.

2. In a double-suction centrifugal liquid pump, a horizontally split casing structure the lower part of which is formed with intake and discharge passages and the upper part of which forms a liquid space, an impeller shaft supported in the lower casing part with its axis in the plane of the fitting of the two parts together, an impeller mounted on said shaft, and a discharge channelway circumferentially surrounding the impeller and clampably supported in place between the two casing parts, said channelway discharging into said casing and the space enclosed by the upper part thereof being in communication around the periphery of said channelway with the discharge passage enclosed by the lower part of said casing.

3. In a double-suction centrifugal liquid pump, a horizontally split casing structure the lower part of which is formed with intake passages 'I'here are no at opposite sides thereof and with discharge passages and the upper partV of which forms a liquid space, an impeller shaft supported by the lower casing part with its axis in the plane of the iitting of the two parts together, an impeller rotatably mounted on said shaft, said inlet passages discharging into the center of the impelled from opposite sides, and a discharge channelway circumferentially surrounding the periphery of the impeller and supported clampably in place therearound between the two casing parts, the said channelway having a peripheral discharge opening tangentially of the impeller into the surrounding liquid space, the 'latter being in communication with the discharge passage enclosed by the lower part of said casing.

4. In a double-suction centrifugal liquid pump, a horizontally split casing, the lower part of said casing being formed with intake and discharge passages opening thereinto upon the same plane with the fitting of the two parts together and the upper part of said casing being of a chamber form providing a liquid space, an impeller shaft supported by the lower casing part with its axis also in the plane of the fitting of the two parts together, an impeller rotatably mounted on said shaft within the casing, an impeller discharge' channelway circumferentially surrounding the impeller and clampably supported in position between the two casing parts, the said channelway being adapted to discharge peripherally from the impeller in a tangential direction into the liquid space, and means directing liquid from the'intake passage intoV opposite sides of the impeller in separation from said space, the latter being in communication with the discharge passage enclosed by the lower part of said casing. l

5. A double-suction centrifugal liquid pump, comprising a horizontally split casing the lower part of which is formed with oppositely extending intake and discharge passages upon the same level and opening thereinto upon the same plane with the litting of the two casing parts together,

Ythe intake passage being bifurcated into opposite side delivery openings into the casing, and the upperV part of which is formed as an open chamber providing a liquid space, with the two together complementarily forming the intake delivery openings into complete annular-like passages directing concentratively into said space at the sides, an impeller shaft supported at opposite sides bythe lower of said casing parts with its axis in the plane of the tting of the two parts together and extending'through said delivery openings, a rotary impeller rotatably mounted on said shaft between the said delivery openings so as to receive the deliveries therefrom at its center on both sides, and an impeller channelway circumferentially surrounding the impeller and supported with a separation all around from the casing walls in clamped position between thetwo casing parts, the said channelway constituting a plurality of peripheral discharge passages formed equi-distantly apart around the impeller circumference and opening or discharging all in the same rotational direction into the liquid space.

6. A double-suction centrifugal liquid pump, comprising a horizontally split casing the lower part of which is formed with oppositely extending intake and discharge passages upon the same .level and opening thereinto upon the same plane with the tting of the two casing parts together,

the intake passage being bifurcated into opposite side delivery openings into the casing, and the upper part of which is formed as an open chamber providingV a liquid space,` an impeller shaft supported at opposite sides by the lower of said casing parts with its axis in the plane of the litting of the two parts together and extending through said delivery openings at the sides, a rotary impeller rotatably mounted on said shaft in position to receive the deliveries from Said delivery openings at its center from both sides, an impellerV discharge channelway circumferentially surrounding the impeller and supported with a separation all around from the casing walls in clamped position between the two casing parts, a suction coupling including a one-Way check valve fitted over the'intake passage opening into the casing, a'vertical stack tted over the discharge passage opening into the casing and extending above tl'ie upper level of the upper casing part, and a vent pipe connection between said stack and the top of the casing.

` 7. A double-suction centrifugal liquid pump, comprising a horizontally split casing the lower part of which is formed with oppositely extending intake and discharge passages upon the same level and opening thereinto upon the same plane with the tting of the two casing parts together, the intake passage being bifurcated into opposite side vdelivery openings into the casing, and the 'upper part o f which is formed as an open chamber providing a liquid space, with the two together complernentarily forming the intake delivery openings -into complete annular-like passages directing concentratively into said space at the sides, an impeller shaft supported at opposite sides by the lower of said casing parts with its axis `in the'plane of the tting of the two parts together and'e'xtending through the centers of saidV delivery openings, a rotary impeller rotatably mounted Von said shaft between the said deliveryV openingsv so as to receive the deliveries therefrom at its center on both sides, an impeller dischargeV channelway peripherally surrounding the impeller and supported with'a separation all around from the casing walls in clamped position between the two casing parts, means substantially enclosing the sides of the impeller against liquid adrnission'thereinto other than at its center from the inlet delivery openings at opposite sides, said'means including plates connected between its center and the edges of said center openings, a suction coupling including a one-way check Valve fitted over the intake passage opening into the casing, a vertical stack fitted over the discharge passage opening into the casing and extending above the upper level of the upper casing part, and a vent pipe connection between said stack and the top of the casing.

8. A double-suction centrifugal liquid pump according to claim 7, wherein said impeller discharge channelway constitutes a plurality of peripheral discharge'passages formed at equal distancesapart around the impeller circumference and opening or discharging tangentially all in the same direction with respect to the impeller rotation, with at least one of said passages vdirected upwardly into the upper part of. the casing and at least one directing downwardly into the bottom of the 'casing toward the discharge passage.

9. A double-suction centrifugal liquid pumpv according to claim 6,' wherein the impeller discharge channelway constitutes ar plurality of peripheral discharge passages formedV at equal distances apart around the impeller circumference and opening or discharging tangentially al1 in the same direction with respect to the impeller rotation.

10. A self-priming centrifugal pump having its impeller rotating on a horizontally disposed axis, a casing horizontally split in the plane of the impeller shaft axis, a housing in which the impeller rotates forming around the periphery of the impeller a passage or passages through which fluid discharges from the impeller into said casing, the latter enclosing and providing around said housing a chamber in which priming water can be retained at a level substantially higher than said other mentioned parts and from the upper part of which air can discharge during priming, the lower part of said casing having means supporting said housing and the upper part having means cooperating with the first named means for clamping said housing in the casing, the upper and lower parts of said casing having complemental parts of a suction passage, and annular means coaxial with the impeller through which it takes in fluid at its central portion from said suction passage.

l1. A self-priming centrifugal pump having its impeller rotating on a horizontally disposed axis, a casing horizontally split in the plane of the impeller shaft axis, a housing in which the impeller rotates forming around the periphery of the impeller a passage or passages through which fluid discharges from the impeller into said casing, the latter enclosing and forming around said housing a chamber in which priming water can be retained at a level substantially higher than the other mentioned parts and from the upper part of which air can discharge during priming, the upper and lower parts of said housing having complemental parts of suction passages at opposite sides of the impeller, annular means coaxial with the impeller by which it is operatively connected with said suction passages for intake of fluid therefrom into the central part of the impeller, said housing being clamped between the upper and lower parts of said casing, bearings for the impeller shaft at opposite sides of said casing, the upper and lower part of said casing having partscooperating to form stuffing boxes for said shaft and pa'ssagesoutside of said suction passages and in communication with said chamber for water sealing the packings in said stuing boxes.

l2, In a self-priming centrifugal pump, the combination with the pump proper having a passage or passages through which fluid discharges from the periphery of its impeller, of a chamber enclosing said pump and into which it discharges, the top of saidv chamber being at an elevation substantially higher than the highest part of said pump proper, a liquid delivery passage extending upwardly from the lower part of said chamber, and an air discharge passage extending from the upper part of said chamber to said liquid delivering passage; said pump, chamber, liquid delivery passage and air discharge passage con'- stituting a system from which liquid is deliverable only at an elevation substantially higher than the liquid level necessary or desirable to be maintained in said chamber for priming and from which air can escape through said air discharge passage during priming.

13. In a self-priming centrifugal pump, the combination with the pump proper having a passage or pasages through which fluid discharges from the periphery of its impeller, of an enclos- 75,

ing casing horizontally split in the plane of the impeller axis, said casing providing above said pump an upwardly extending air separating chamber and in its lower part a discharge passage with which said chamber communicates through flow passages around the impeller housing between it and the interior walls of said casing, a liquid delivery pipe extending upwardly from said discharge passage in the lower part of said casing, and an air discharge passage extending from the upper part of said air separating chamber` to said liquid delivery passage.

14. A self-priming centrifugal pump having its impeller rotating on a horizontally disposed axis, a housing providing around the periphery of the impellerl successively arranged passages through which fluid discharges from the impeller, a casing providing around said housing an upper air separating chamber and a bottom discharge passage and passages connecting said air separating chamber and bottom discharge passage, a liquid delivery pipe extending upwardly from said bottom discharge pipe, and an air discharge pipe extending from said chamber to said liquid delivery pipe. Y

' l5. A self-priming centrifugal pump having its impeller rotating on a horizontally disposed axis, a housing providing around the periphery of the impeller oppositely arranged centrifugally extending volute type passages opening lengthwise of said passages from extended segments of the impeller and gradually enlarging toward and open at their forward ends, a casing providing around said housing an upper air separating chamber and a bottom discharge passage and connecting passages, one of said volute type passages being an upflow passage extending around the ascending side of the impeller periphery and discharging upwardly into said chamber, the other volute type passage being a downflow passage extending around the descending side of the impeller periphery and discharging into said bottomdischarge passage, the arrangement permitting upiiow around said upflow volute type passage bebetween it and the interior Walls of the casing into the upper separating chamber and downflow from the latter around the downow volute type passage between it and said casing into said bottom discharge passage, a liquid delivery pipe extending upwardly from said bottom .discharge pipe, and an air discharging passage extending from 'the upper part of said air separating chamber to said liquid discharge pipe.

16. A self-priming centrifugal pump having a closed type impeller-rotating on a horizontally disposed axis, suction passages at opposite sides of the-impeller through which the impeller takes in fluid at its central portion, an annular housing in which the impeller rotates forming around the periphery of the impeller a passage or passages through which iluid discharges from the impeller, a casing enclosing and providing around said housing a chamber in'which priming Water can be retained at a level substantially higher than the other mentioned parts and from the upper part of which air can discharge during priming, annular chambers adjacent to the periphery of the impeller at opposite sides thereof having apertures for admitting Water from said first mentioned chamber, there being clearance between the periphery of the impeller and said housing permitting restricted flow of Water from said annular chambers laterally to the -periphery of the'impeller.

17. A self-priming centrifugal pump having a closed type impeller rotating on a horizontally disposed axis, suction passages at opposite sides of the impeller through which the impeller takes in fluid at its central part, an annular housing in which the impeller rotates, said housing providing around the periphery of the impeller a passage or passages through which fluid discharges from the impeller, and a casing enclosing and providing around said housing a chamber in which priming Water may be maintained at a level substantially higher than the other mentioned parts and from the upper part of which air can discharge during priming, there being clearance between said housing and impeller permititng restricted flow of liquid laterally to the periphery of the impeller; and annular chambers adjacent to the periphery of the impeller at opposite sides thereof having inlets communicating with the first mentioned chamber.

18. In a pump as set forth in claim 17, said annular chambers having Walls extending between the sides of the impeller housing and the inner walls of the irst mentioned chamber, said Walls being provided with restricted openings controlling the amount of liquid discharged from the annular chambers through said clearances.

19. In a pump as set forth in claim 17, said annular chambers having Walls extending between the sides of the impeller housing and outer Walls of the central intake passages of the impeller and spaced from the sides of the impeller, said Walls being provided with restricted openings controlling the amount of liquid discharged from the annular chambers through said clearances.

HERBERT E. RUPP. 

